This invention relates to a vacuum processing method of using a vacuum processing unit including: a stage on which a substrate to be processed is adapted to be placed; a vacuum processing mechanism that conducts a vacuum process to the substrate to be processed placed on the stage; and a controller that controls the vacuum processing mechanism. In addition, this invention relates to the vacuum processing unit. Furthermore, this invention relates to a sensor substrate that is placed on the stage.
The structure of a conventional vacuum processing unit is explained with reference to FIG. 6.
FIG. 6 shows a schematic sectional view of an etching unit 100 that is an example of a vacuum processing unit. In the etching unit 100, a processing chamber 102 is formed in a processing container 104 that has a substantially cylindrical shape, that can be hermetically closed and that is made of aluminum whose surface has been subjected to an anodic oxidation process. The processing container 104 itself is connected to ground via a ground wire 106.
An insulating support plate 108 is provided in a base portion of the processing chamber 102. A substantially cylindrical susceptor (stage) 110 that forms a lower electrode in order to place a substrate to be processed (for example, a 6-inch wafer) W thereon is contained in a vertically movable manner above the insulating support plate 108.
The susceptor 110 is supported by an elevation shaft 112 that freely passes through the insulating support plate 108 and a base portion of the processing container 104. The elevation shaft 112 is vertically movable by means of a driving motor 114 disposed outside the processing container 104. Thus, when the driving motor 114 operates, the susceptor 110 can be vertically moved in a direction shown by a two-way arrow in FIG. 6. In addition, in order to secure airtightness of the processing chamber 102, an extendable hermetic bellows 116 is arranged around the elevation shaft 112 between the susceptor 110 and the insulating support plate 108.
The susceptor 110 is made of aluminum whose surface has been subjected to an anodic oxidation process. A heating means (not shown), such as a ceramics heater, and a cooling-medium circulating way (not shown), which is to cause a cooling medium from an outside cooling-medium source (not shown) to circulate, are provided in the susceptor 110. The heating means and the cooling-medium circulating way are formed to be automatically controlled by a temperature controlling mechanism (not shown). Thus, it is possible to maintain a substrate to be processed W on the susceptor 110 at a predetermined temperature.
An electrostatic chuck 118 for sticking to and holding the substrate to be processed W is provided on the susceptor 110. The electrostatic chuck 118 has a structure wherein an electric conductive thin film is sandwiched between upper and lower polyimide resin elements. The electrostatic chuck 118 is adapted to be applied a voltage (for example, a voltage of 1.5 kV to 2.0 kV) from a high-voltage direct-current source 120 that is disposed outside the processing container 104. By means of coulomb force created by applying the voltage, the substrate to be processed W is adapted to be stuck to and held by an upper surface of the electrostatic chuck 118.
On an upper peripheral area of the susceptor 110, a substantially circular focus ring 122 is disposed surrounding the electrostatic chuck 118. The focus ring 122 is made of crystal that has insulating performance, and has a function to restrain a diffusion of plasma that may be generated between the susceptor 110 and an upper electrode 124 as described below and a function to cause ions in the plasma effectively to reach the substrate to be processed W.
A substantially disk-shaped upper electrode 124 is arranged at a position facing a placing surface of the susceptor 110. The upper electrode 124 is made of electric conductive single-crystal Silicon and has a plurality of through-holes 124a. An upper-electrode supporting member 126 that is made of electric conductive aluminum and that has substantially the same diameter as the upper electrode 124 is arranged above the upper electrode 124.
An opening 126a is formed in the upper-electrode supporting member 126 on a side of the upper electrode 124. Thus, in a state wherein the upper electrode 124 is attached to the upper-electrode supporting member 126, a space 130 is formed between the upper electrode 124 and the upper-electrode supporting member 126.
A substantially circular shield ring 132 that is made of crystal having insulating performance is arranged from a lower peripheral portion of the upper electrode 124 to a central portion of an outside curcumferential surface of an insulating ring 128. The shield ring 132 has a function to form a gap together with the focus ring 122 and to restrain a diffusion of plasma, the gap being narrower than a gap between the electrostatic chuck 118 and the upper electrode 124.
A gas inlet port 134 is connected to a substantially central upper portion of the space 130. A gas inlet tube 138 is connected to the gas inlet port 134 via a valve 136. Respective corresponding gas supply sources 152, 154 and 156 are connected to the gas inlet tube 134 via valves 140, 142 and 144 and mass flow controllers (MFC) 146, 148 and 150 that are for adjusting respective corresponding flow rates.
Ar can be freely supplied from the gas supply source 152. O2 can be freely supplied from the gas supply source 154. C3F6 can be freely supplied from the gas supply source 156. The respective gases from the gas supply sources 152, 154 and 156 are introduced into the processing chamber 102 via the gas inlet tube 138, the gas inlet port 134, the space 130 and the through-holes 124a, and then uniformly flow toward a surface to be processed of the substrate to be processed W.
A discharging tube 160 leading to a vacuum means 158 such as a vacuum pump is connected to a lower portion of the processing container 104. Thus, a vacuum of an optional level such as several mTorr to several hundred mTorr can be created in the processing chamber 102 via a gas-discharging plate 162 consisting of for example a punched plate, and the vacuum can be maintained.
Electric power from a first high-frequency power source 164 that outputs high frequency power whose frequency is about several hundred kHz (for example 800 kHz) can be supplied to the susceptor 110 via a matching device 166. On the other hand, electric power from a second high-frequency power source 168 that outputs high frequency power whose frequency is not less than 1 MHz (for example 27.12 MHz), which is greater than that of the first high-frequency power source 164, can be supplied to the upper electrode 124 via a matching device 170 and the upper-electrode supporting member 126.
Next, an operation in a case wherein an etching process is conducted to a substrate to be processed W, which consists of for example SiO2, by using the above etching unit 100 is explained below.
At first, the substrate to be processed W is placed on the susceptor 110. Then, a predetermined voltage from the high-voltage direct-current source 120 is applied to the electric conductive thin film in the electrostatic chuck 118, so that the substrate to be processed W is sucked to and hence held by the electrostatic chuck 118. Since the susceptor 110 is adjusted to a predetermined temperature by means of a temperature-adjusting means not shown, a surface temperature of the substrate to be processed W held on the susceptor 110 is set at a desired temperature (for example not more than 120xc2x0 C.) even when the substrate is processed.
Then, a vacuum is created in the processing chamber 102 by means of the vacuum means 158. In addition, gases necessary for the etching process are supplied at respective predetermined rates from the gas supply sources 152, 154 and 156, so that a pressure in the processing chamber 102 is set and maintained at a predetermined vacuum level such as 40 mTorr.
Herein, the respective gases Ar, O2 and C3F6 supplied from the gas supply sources 152, 154 and 156 are adjusted to the predetermined flow rates by means of the respective corresponding mass-flow controllers 146, 148 and 150 and the valves 140, 142 and 144, and then mixed. The mixed gas is introduced onto the substrate to be processed W via the gas inlet tube 138, the gas inlet port 134, the space 130 and the through-holes 124a. 
In the mixed gas, for example, the flow rates of the respective gases are adjusted in such a manner that a flow-rate ratio of O2 to C3F6 is 0.1xe2x89xa6O2/C3F6xe2x89xa61.0, and open levels of the respective valves 140, 142 and 144 are adjusted in such a manner that a partial pressure of C3F6 is 0.5 mTorr to 2.0 mTorr.
Then, when a high-frequency electric power having a frequency of 27.12 MHz and a power such as 2 kW is supplied to the upper electrode 124 from the second high-frequency power source 168, plasma is generated between the upper electrode 124 and the susceptor 110. At the same time, a high-frequency electric power having a frequency of 800 kHz and a power such as 1 kW is supplied to the susceptor 110 from the first high-frequency power source 164.
The process gas in the processing chamber 102 is decomposed by the generated plasma to generate etchant ions. The etchant ions etch the SiO2 film of the surface of the substrate to be processed W, while incident speed of the etchant ions are controlled by the relatively low high-frequency supplied to the susceptor 110.
More detailed explanation of the above etching unit 100 is disclosed by Japanese Patent Laid-Open Publication No.10-199869.
In order to properly control a vacuum processing unit, it is effective to detect information about a processing state by the vacuum processing unit. As a technique for detecting the information about the processing state by the vacuum processing unit, a technique of mounting various sensors in the vacuum processing unit has been developed.
Such a technique is disclosed by for example Japanese Patent Laid-Open Publication No.6-76193. The invention disclosed in Japanese Patent Laid-Open Publication No.6-76193 is an invention wherein: a sensor and a transmitter are mounted in a vacuum processing unit, and information measured by the sensor is transmitted outside of the vacuum processing unit by the wireless transmitter. The invention has an advantage that wiring is unnecessary for transmitting the information measured by the sensor, so that the information measured by the sensor can be easily obtained even when the vacuum processing unit is in a vacuum state. In addition, Japanese Patent Laid-Open Publication No.6-76193 also refers to it that the sensor and the transmitter can be mounted on a substrate to be processed.
However, in the content disclosed by Japanese Patent Laid-Open Publication No.6-76193, as shown in respective drawings thereof, the sensor protrudes from on the substrate to be processed.
Inventors of this invention have found that it is troublesome to process the substrate to be processed wherein the sensor or the transmitter is protruded from on the substrate to be processed.
The first reason thereof is that: a process to be conducted by the vacuum processing unit may be conducted not in accordance with a specification thereof, owing to the sensor or transmitter protruded from on the substrate to be processed, because a design of the vacuum processing unit for the specification is based on a supposed horizontal surface of the substrate to be processed.
The second reason thereof is that: mounting of the sensor and the transmitter on each substrate to be processed, which is a product, is not practical because of various costs, while a following problem is generated when a substrate to be processed, from which the sensor and the transmitter are protruded, is used as a kind of xe2x80x9cmodel substratexe2x80x9d. That is, although the sensor and the transmitter are protruded from the xe2x80x9cmodel substratexe2x80x9d, a substrate to be processed for an actual product has no such a protrusion, so that it cannot be known whether information obtained from the sensor of the xe2x80x9cmodel substratexe2x80x9d is truly applicable for the process to the substrate to be processed as the product. For example, it can be thought that a state of the gas flows in the vacuum processing unit may delicately influence the state of the vacuum process, and that the state of the gas flows may be greatly changed by presence of such a protrusion.
In addition, as a technique for providing a sensor on a xe2x80x9cmodel substratexe2x80x9d in such a manner that the sensor is not protruded from the substrate, there is a technique disclosed by Japanese Patent Laid-Open Publication No.9-189613 by the applicant of this invention. The invention of the publication is an invention wherein a temperature-measurement point is formed in the substrate, and a measured signal is taken from the point via a stage.
FIG. 7 is a plan view of a wafer for a temperature measurement 201 that is disclosed in the above publication. A substrate 202 for the wafer for the temperature measurement 201 is made of the same silicon as that forming a common semiconductor device.
For example, five rank and five file temperature-measurement points, that is, temperature-measurement points A1 to A5, B1 to B5, C1 to C5, D1 to D5 and E1 to E5 are formed on an upper surface of the wafer for the temperature measurement 201. These temperature-measurement points A1 to E5 are patterned onto the substrate 202. A device structure thereof is patterned onto the substrate 52 by using an etching process or a film-forming process, which are common processes for manufacturing semiconductor devices.
For example, if an alumel-chromel-thermocouple is used, as shown in FIG. 8, an interlayer insulating film 203 formed on the silicon substrate 202 is etched into longitudinal grooves in accordance with a predetermined pattern, the grooves are then filled with alumel 204 by a metal-deposition process, chromel 205 is then patterned thereon in belt-shaped patterns of a lateral direction, and contact points thereof can be used as the temperature-measurement points.
The respective temperature-measurement points A1 to E5 that have been patterned on the substrate 202 via the above steps are in a uniformly-formed state, because the points are pattered on the substrate 202, differently from a conventional case wherein the points are attached to the substrate by means of adhesive. Thus, the points are free from conventional problems such as coming off of the adhesive, unevenness of temperature depending on an adhesively attached state or contamination in the processing chamber owing to the coming off of the adhesive.
However, in the invention disclosed by Japanese Patent Laid-Open Publication No.9-189613, the detected information is limited to the temperature and taken via a signal processor 206 and a terminal board 207 as it is. Thus, wiring is basically necessary correspondingly to the number of measurement points.
This invention is intended to solve the above problems. The object of this invention is to provide a vacuum processing method, a vacuum processing unit and a sensor substrate as a xe2x80x9cmodel-substratexe2x80x9d, in which an outside shape of a sensor substrate as a xe2x80x9cmodel-substratexe2x80x9d is not different from a substrate to be processed for a product, information detected by the sensor substrate is not limited to temperature, and a process of transmitting the detected information is more convenient.
In addition, the term xe2x80x9cvacuum processxe2x80x9d in the specification is used as a term having a very broad meaning, that is, generally represents xe2x80x9cany process in a closed space whose pressure can be reduced below atmospheric pressurexe2x80x9d
This invention is a vacuum processing method of using a vacuum processing unit including: a stage on which a substrate to be processed is adapted to be placed; a vacuum processing mechanism that conducts a vacuum process to the substrate to be processed placed on the stage; and a controller that controls the vacuum processing mechanism; comprising; a step of placing a sensor substrate on the stage part, the sensor substrate being formed in such a manner that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed placed on the stage, the sensor substrate having a detecting device that detects information about a vacuum processing state and an information-processing device that processes the information detected by the detecting device; a step of conducting a vacuum process to the sensor substrate by means of the vacuum processing mechanism; a step of detecting information about a vacuum processing state by means of the detecting device when the sensor substrate is subjected to the vacuum process; a step of processing the information detected by the detecting device by means of the information-processing device; a step of removing the sensor substrate from the stage; a step of placing a substrate to be processed on the stage; and a step of conducting a vacuum process to the substrate to be processed, by controlling the vacuum processing mechanism by means of the controller based on the information about the vacuum processing state processed by the information-processing device.
According to the vacuum processing method of the invention, since the sensor substrate is formed in such a manner that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed, the information about the vacuum processing state detected by the detecting device of the sensor substrate is very useful information for a vacuum process to the substrate to be processed.
In addition, according to the vacuum processing method of the invention, since the information detected by the detecting device is processed by the information-processing device of the sensor substrate, a process of transmitting the detected information is more convenient.
In the vacuum processing method of the invention, if the vacuum process is a plasma process, in particular a plasma-etching process, it is especially effective that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed, because identity of process environment such as gas flow environment can be secured.
In addition, in the vacuum processing method of the invention, it is preferable that the substrate to be processed is a semiconductor wafer or a glass substrate for an LCD.
In addition, in the vacuum processing method of the invention, it is preferable that the information-processing device has a storing device that stores the information detected by the detecting device. In the case, the information stored by the storing device may be transmitted to and analyzed by the controller. Alternatively, an analyzing part can be provided separately from the controller.
In addition, in the vacuum processing method of the invention, it is preferable that the information-processing device has a transmitting device that transmits the information detected by the detecting device to the controller via a real-time wireless communication. In the case, the information transmitted by the transmitting device may be analyzed by the controller, so that a controlling state of the vacuum processing mechanism can be changed during the process.
In addition, in the vacuum processing method of the invention, if the sensor substrate has one or more microscopic holes and the detecting device is arranged in the microscopic holes, the detecting device can detect a state in a course of a microscopic-hole forming process that is one manner of the vacuum process. Especially, if a plurality of aspect ratios are set for a plurality of microscopic holes, a plurality of vacuum-state information corresponding to a plurality of courses can be obtained.
In addition, in the vacuum processing method of the invention, it is preferable that the detecting device is adapted to detect one of a power density, a Vdc, a xcex94Vdc, infrared-ray intensity, ultraviolet-ray intensity, visible-ray intensity, temperature, molecular weight, ion current, acceleration, a distortion, a displacement and a sound.
Next, this invention is a sensor substrate to be placed on a stage of a vacuum processing unit that includes the stage to place a substrate to be processed thereon; the sensor substrate being formed in such a manner that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed placed on the stage; and the sensor substrate having a detecting device that detects information about a vacuum processing state and an information-processing device that processes the information detected by the detecting device.
According to the sensor substrate of the invention, since the sensor substrate is formed in such a manner that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed, the detecting device can detect information about a vacuum processing state which is very useful for a vacuum process to the substrate to be processed.
In addition, according to the sensor substrate of the invention, since the information-processing device can process the information detected by the detecting device, a process of transmitting the detected information is more convenient.
In the sensor substrate of the invention, if the vacuum process is a plasma process, in particular a plasma-etching process, it is especially effective that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed, because identity of process environment such as gas flow environment can be secured.
In addition, in the sensor substrate of the invention, the substrate to be processed that is herein assumed is generally a semiconductor wafer or a glass substrate for an LCD.
In addition, in the sensor substrate of the invention, it is preferable that the information-processing device has a storing device that stores the information detected by the detecting device. In the case, for example, the information stored by the storing device is analyzed later.
In addition, in the sensor substrate of the invention, it is preferable that the information-processing device has a transmitting device that transmits the information detected by the detecting device to the vacuum processing unit via a real-time wireless communication. In the case, the information transmitted by the transmitting device is analyzed by the vacuum processing unit, so that a controlling state of the vacuum processing mechanism can be changed during the process.
Alternatively, the information can be transmitted to a high-speed/high-performance computer via an Internet or an Intranet, data-processed and/or analyzed by the computer and fed back to the vacuum processing unit as real-time information.
Alternatively, if the information is arranged into data following change in time of each characteristic, each process parameter can be changed to compensate for the change in time.
In addition, in the sensor substrate of the invention, if the sensor substrate has one or more microscopic holes and the detecting device is arranged in the microscopic holes, the detecting device can detect a state in a course of a microscopic-hole forming process that is one manner of the vacuum process. Especially, if a plurality of aspect ratios are set for a plurality of microscopic holes, a plurality of vacuum-state information corresponding to a plurality of courses can be obtained.
In addition, in the sensor substrate of the invention, it is preferable that the detecting device is adapted to detect one of a power density, a Vdc, a xcex94Vdc, infrared-ray intensity, ultraviolet-ray intensity, visible-ray intensity, temperature, molecular weight, ion current, acceleration, a distortion, a displacement and a sound.
Next, this invention is a vacuum processing unit comprising; a stage on which a substrate to be processed is adapted to be placed; a vacuum processing mechanism that conducts a vacuum process to the substrate to be processed placed on the stage; and a controller that controls the vacuum processing mechanism; wherein the controller is adapted to control the vacuum processing mechanism based on information from a sensor substrate that has substantially the same shape and substantially the same size as the substrate to be processed placed on the stage.
According to the vacuum processing unit of the invention, since the sensor substrate is formed in such a manner that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed, the information about the vacuum processing state detected by the detecting device of the sensor substrate is very useful information for a vacuum process to the substrate to be processed.
In the vacuum processing unit of the invention, if the vacuum process is a plasma process, in particular a plasma-etching process, a great advantageous effect can be brought by that the sensor substrate has substantially the same shape and substantially the same size as the substrate to be processed, because identity of process environment such as gas flow environment can be secured.
In addition, in the vacuum processing unit of the invention, it is preferable that the substrate to be processed is a semiconductor wafer or a glass substrate for an LCD.
In addition, in the vacuum processing unit of the invention, it is preferable that the sensor substrate has a detecting device that detects information about a vacuum processing state and a storing device that stores the information detected by the detecting device. In the case, for example, the information stored by the storing device is transmitted to and analyzed by the controller.
In addition, in the vacuum processing unit of the invention, it is preferable that the sensor substrate has a detecting device that detects information about a vacuum processing state and a transmitting device that transmits the information detected by the detecting device to the controller via a real-time wireless communication. In the case, the information transmitted by the transmitting device is analyzed by the controller, so that a controlling state of the vacuum processing mechanism can be changed during the process.
In addition, in the vacuum processing unit of the invention, if the sensor substrate has one or more microscopic holes and the detecting device is arranged in the microscopic holes, the detecting device can detect a state in a course of a microscopic-hole forming process that is one manner of the vacuum process. Especially, if a plurality of aspect ratios are set for a plurality of microscopic holes, a plurality of vacuum-state information corresponding to a plurality of courses can be obtained.
In addition, in the vacuum processing unit of the invention, it is preferable that the detecting device is adapted to detect one of a power density, a Vdc, a xcex94Vdc, infrared-ray intensity, ultraviolet-ray intensity, visible-ray intensity, temperature, molecular weight, ion current, acceleration, a distortion, a displacement and a sound.